Abstrict In a gyratory crusher, a main shaft having a tapered mantle supporting
portion extending through a correspondingly tapered bore in the
crusher mantle to support the mantle on the shaft, and a bearing
sleeve fitted about the end of the shaft releasably securing the
crusher mantle to the tapered portion of the shaft.
Claims The embodiments of the invention in which an exclusive property
or privilege is claimed are defined as follows:
1. In a gyratory crusher including a lower frame, an upper frame
mounted on the lower frame, a crusher mantle having a tapered internal
bore extending through the mantle, and a shaft having a correspondingly
tapered mantle supporting portion projecting through the bore in
generally contiguous supportive engagement with the mantle to support
the mantle on the shaft, the improvement comprising:
a bearing journal projecting from said supporting portion to form
the end of the shaft;
a bearing sleeve releasably secured about said journal including
shoulder means engaging the crusher mantle to restrain axial displacement
of the mantle along the shaft;
stationary first bearing means retained by the upper frame retaining
said bearing sleeve and journal and second bearing means retained
by the lower frame supporting the shaft for gyratory movement about
the axis of said first bearing means during operation of the crusher;
and
sleeve fastening means releasably securing the bearing sleeve to
the shaft at the outermost end of the journal remote from bending
loads imposed on the shaft by the mantle during operation of the
crusher.
2. The improvement according to claim 1 and
said shoulder means including a threaded annular section on the
sleeve, and a head nut threadably secured to said section in abutting
relation to the crusher mantle.
3. The improvement according to claim 2 and
the interior of said sleeve being counterbored to prevent engagement
between the sleeve and the shaft in the proximity of said threaded
annular section.
4. The improvement according to claim 1 and
said sleeve being releasably secured to the journal in heat shrink-fit
relation.
5. The improvement according to claim 1 and said sleeve fastening
means including a threaded lug projecting from the outermost end
of the journal and a sleeve nut sized to axially overlie the sleeve
threadedly secured to the lug.
6. The improvement according to claim 5 and second key means coupling
the sleeve nut and the sleeve to prevent relative rotational movement
therebetween.
7. The improvement according to claim 1 and said sleeve fastening
means including an annular retaining ring sized to axially overlie
the outermost ends of the journal and the sleeve, and mechanical
fastening means releasably securing said ring to the shaft.
8. The improvement according to claim 1 and said sleeve including
an inwardly projecting annular lip sized to overlie the marginal
edge of the outermost end of the journal; and
mechanical fastening means releasably securing said lip to the
journal.
9. The improvement according to claim 1 and said fastening means
including a plurality of axially extending exterior slots in said
journal spaced about its periphery and said sleeve having a corresponding
plurality of interior slots in registry with said exterior slots
forming a plurality of radially extending cavities between the journal
and the sleeve; and
a relatively rigid adhesive material filling said cavities obstructing
relative rotational movement between the journal and the sleeve.
10. The improvement according to claim 1 and said fastening means
including an exterior groove about the periphery of said journal
and said sleeve having a corresponding interior groove in registry
with said exterior groove to form an annular chamber between the
journal and the sleeve; and
a relatively rigid adhesive material filling said annular chamber
obstructing relative axial movement between the journal and the
sleeve.
11. The improvement according to claim 10 and said journal having
a plurality of axially extending exterior slots spaced about its
periphery and said sleeve having a corresponding plurality of interior
slots in registry with said exterior slots to form a plurality of
radially extending cavities opening into said annular chamber; and
said rigid adhesive material filling said cavities and said chamber
to form an adhesive bond between the journal and the sleeve and
obstruct relative movement therebetween.
Description FIELD OF THE INVENTION
The present invention relates to gyratory crushers and, in particular,
to the main shaft supporting the crusher head or mantle within the
crusher.
DESCRIPTION OF THE PRIOR ART
As exemplified by U.S. Pat. Nos. 2883218 and 4034922 a gyratory
crusher typically includes a main shaft provided with a tapered
portion which supports the crusher head or mantle through a correspondingly
tapered internal bore extending through the mantle. To secure the
mantle to the shaft, a threaded section has generally been provided
on the shaft immediately above the tapered portion supporting the
mantle for receiving a head nut which forces the mantle against
the tapered portion of the shaft. While this type of arrangement
has proven to be satisfactory for most crusher installations, experience
has indicated that the relatively abrupt changes in the cross-sectional
area of the shaft above and below the threaded section have resulted
in high local stress concentrations in these regions of the shaft.
These stress concentrations are in addition to the substantial stresses
generated by the cyclic bending loads applied to the shaft by the
mantle during operation of the crusher. The result has been the
development of fatigue cracks or fractures in the threaded section
of the shaft as well as immediately above and below it where the
highest stresses occur due to the abrupt changes in the cross-sectional
area of the shaft. Over a period of time the cracks continue to
grow and ultimately render the shaft unserviceable requiring that
the crusher be taken out of service and the shaft replaced before
crushing operations can be resumed. Similarly, if the manganese
steel mantle works loose on the shaft due to localized work hardening
which causes it to expand about the axis of the shaft, the rocking
motion of the mantle can shear off the threads securing it to the
shaft.
SUMMARY OF THE INVENTION
The present invention relates to gyratory crushers and, in particular,
to a main shaft and bearing sleeve arrangement supporting the crusher
head or mantle wihin the crusher.
The main shaft includes a tapered head supporting portion which
extends through a correspondingly tapered bore in a conically shaped
crusher mantle to support the mantle on the shaft. The end of the
shaft is provided with a bearing journal fitted with a replaceable
sleeve arrangement retained in a stationary bushing on the frame
of the crusher which accommodates gyratory movement of the shaft
about the bushing during crushing operations. The sleeve arrangement,
which is releasably secured to the bearing journal at the low stressed,
outermost end of the shaft, includes a head nut which abuts the
mantle to secure it to the tapered portion of the shaft.
From the foregoing, it can be seen that the invention contemplates
an arrangement wherein abrupt structural discontinuities in the
normally high-stressed regions of the main shaft have been essentially
eliminated to minimize the development of fatigue fractures in the
shaft while at the same time providing an arrangement which can
be easily maintained and repaired in the field, it being understood
that various changes can be made in the arrangement, form and construction
of the apparatus disclosed herein without departing from the spirit
and scope of the invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross-sectional view through a gyratory crusher
equipped with the crusher shaft and sleeve arrangement embodying
the invention;
FIG. 2 is an enlarged partial cross-sectional view of the crusher
main shaft and sleeve arrangement as it is shown in FIG. 1;
FIG. 3 is a fragmentary elevational view taken substantially along
line III--III in FIG. 2;
FIG. 4 is a fragmentary elevational view taken substantially along
line IV--IV in FIG. 2;
FIG. 5 is a partial cross-sectional view similar to FIG. 2 showing
an alternative embodiment of the invention;
FIG. 6 is a fragmentary elevational view taken substantially along
line VI--VI in FIG. 5;
FIG. 7 is a top view of the crusher shaft showing another embodiment
of the invention;
FIG. 8 is a partial cross-sectional view taken substantially along
line VII--VII in FIG. 7;
FIG. 9 is a top view of the crusher shaft showing yet another embodiment
of the invention; and
FIG. 10 is a partial cross-sectional view taken substantially along
line X--X in FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 the gyratory crusher 1 embodying the invention
includes a lower frame 2 provided with a vertical hub 3 an upper
frame 4 forming the outer shell of the crusher chamber 5 a top
frame or spider 6 mounted on the upper frame 4 and a centrally
located gyratable main shaft 7. The main shaft 7 includes a tapered
or frustoconically shaped mantle supporting portion 8 which extends
through a correspondingly tapered bore 9 in a conically shaped crusher
mantle 10 to support the mantle on the shaft 7. As will be described,
the cross-section of the upper end of the shaft 7 gradually converges
to form a bearing journal 11 extending from the tapered portion
of the shaft which is fitted with a cylindrical bearing sleeve 12
rotatably retained within a bearing bushing 13 secured within a
coaxially aligned hub 14 in the spider 6.
The main shaft 7 which is carried on an axial thrust bearing 18
mounted on the lower frame 2 beneath the shaft, is rotatably journaled
within an eccentric sleeve bearing carried within the vertical hub
3 to direct the gyratory movement of the shaft. As shown in FIG.
1 the sleeve bearing includes an eccentric 21 having an outer cylindrical
surface 22 journaled within the hub 3 and an eccentrically disposed
internal bore 23 which receives the shaft 7 along an axis inclined
to the external surface of the sleeve. The eccentric is carried
by a supporting bearing 24 on the lower frame 2 and includes a ring
gear 25 secured about its periphery which is driven by a driving
pinion 26 mounted on a horizontally extending drive shaft 27 journaled
within the lower frame 2. The drive shaft 27 is connected with a
suitable rotary drive (not shown) which in turn rotates the eccentric
21 through the ring gear 25 and pinion 26 to effect gyratory movement
of the main shaft about the bushing 13 during crushing operations.
As shown in FIGS. 1 and 2 the bearing sleeve 12 extends generally
coextensively with the bearing journal 11 and includes an externally
threaded annular shoulder 28 about its lower periphery threadably
receiving a head nut 29. The head nut 29 abuts the upper edge 30
of the mantle 10 to secure it to the tapered portion of the main
shaft 7 and at least one rod or dowel 31 is welded in a corresponding
pair of semi-circular keyways in the head nut and the mantle to
prevent rotation between these members after the head nut is secured
in position. Additionally, to abate fretting corrosion of the main
shaft in the normally high stressed portion of the shaft at the
base of the bearing journal 11 the sleeve is counterbored as indicated
at 28' to prevent engagement between the sleeve and the main shaft
in the proximity of the threaded annular shoulder 28.
When the bearing sleeve 12 is installed on the bearing journal
11 it is initially heated so that as it cools it forms a heat-shrink
type fit releasably securing it to the journal. While this heat-shrink
type connection will generally be sufficient to secure the sleeve
and thus the crusher mantle on the shaft during normal crusher operations,
the invention also specifically provides for securing the sleeve
to the journal 11 in the low stressed, uppermost region of the shaft.
As best shown in FIGS. 2 and 3 a threaded lug 34 is provided on
the end of the journal which is adapted to receive a sleeve nut
35 which axially overlies an inwardly projecting annular lip 36
on the upper end of the sleeve 12. The annular lip 36 is secured
against the upper marginal edge surface of the shaft 7 by the sleeve
nut 35 which is in turn rigidly coupled to the sleeve 12 by at least
one key 37 welded in a corresponding pair of keyways 38 and 39 spaced
about the peripheries of the sleeve nut and the sleeve. It should
be noted that the direction of the threading on the lug 34 and the
sleeve nut 35 is such that the sleeve nut is essentially self-tightening.
More particularly, in the present arrangement the eccentric is driven
in a clockwise direction so that the materials moving through the
crusher tend to rotate the mantle in a counterclockwise direction.
Thus, the self-tightening head nut 29 has a tendency to rotate in
a clockwise direction on the threaded annular shoulder 28. Should
the threads 28 become damaged and locked, a torsional force would
be transmitted through the sleeve to the sleeve nut via the key
37 so as to constantly urge the sleeve nut into engagement with
the annular lip of the sleeve, thereby preventing excessive rotation
of the sleeve on the main shaft.
FIGS. 5 and 6 show a second embodiment of the invention wherein
like numerals designate the elements which are substantially the
same as those of the first embodiment shown in FIGS. 1-4. In this
embodiment, a cylindrical bearing sleeve 40 is provided with a pair
of upwardly opening radial slots 41 which are adapted to receive
a corresponding pair of axially projecting teeth 42 on a washer
43 interposed between the sleeve nut 35 and the sleeve 40. In this
arrangement, the washer 43 is welded as indicated at "w"
to the self-tightening sleeve nut 35 after it is secured in the
sleeve retaining position shown in the drawings to provide the torsional
rigidity effected by the keys 37 in the first embodiment.
FIGS. 7 and 8 show another embodiment of the invention wherein
a cylindrical bearing sleeve 50 is retained on the bearing journal
11 by a retaining ring 51 sized to axially overlie the outermost
ends of the journal 11 and the sleeve 50. As shown in the drawings,
a plurality of cap screws 52 or the like are spaced about the ring
51 to secure it to the bearing journal 11.
FIGS. 9 and 10 show yet another embodiment of the invention wherein
a cylindrical bearing sleeve 60 is secured to the bearing journal
11 by an adhesive epoxy backing compound which hardens to form a
rigid slot and key arrangement adapted to restrain axial and rotational
movement between the sleeve and the journal. As shown in the drawings,
the journal 11 is provided with an exterior peripheral groove 61
about which an interior groove 62 in the sleeve 60 is aligned to
form an annular chamber 63 between the journal 11 and the sleeve
60 and similarly, a plurality of radially extending slots 64 and
65 spaced about the respective peripheries of the bearing journal
and the sleeve are aligned to provide a plurality of radially extending
cavities 66. Considering the foregoing, it can be seen that when
a hardenable adhesive such as an epoxy backing compound is injected
into the cavities 66 and the annular chamber 63 a rigid adhesive
bond is formed between the sleeve and the journal as the epoxy hardens
which also provides a rigid key-like member restraining relative
movement between the sleeve and the journal.
In view of the above, it can be seen that the main shaft in each
of the foregoing embodiments is essentially free of abrupt cross-sectional
discontinuities in the normally high-stressed region of the shaft
proximate the crusher mantle. As a result, the susceptibility of
the shaft to the cracking and fatigue fracture experienced with
the main shaft designs discussed above in regard to the prior art
has been substantially reduced. Moreover, in the event the crusher
head works loose on the shaft due to localized work hardening or
the like, generally only the threading on the relatively inexpensive
and easily replaced bearing sleeve will be damaged. Thus, the crusher
can be promptly put back in service by simply replacing the bearing
sleeve.
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